The present invention relates to methods and apparatus for treating cardiac arrhythmia, and particularly relates to an implantable apparatus that can treat both atrial and ventricular arrythmia with the implantation of two transvenous leads.
Atrial fibrillation is one of the most common cardiac arrhythmia. Health consequences associated with atrial fibrillation include decreased cardiac output, less regular ventricular rhythm, the formation of blood clots in the atrial appendages, and an increased incidence of stroke. While some drugs are available for the treatment of atrial fibrillation, they have a number of side effects which reduce their therapeutic utility.
Unlike patients afflicted with ventricular fibrillation, patients afflicted with atrial fibrillation are conscious. The pain associated with the administration of the defibrillation shock can be severe, and there is a need for means of carrying out atrial defibrillation in a manner that is less painful to the patient being treated. One means for reducing the pain associated with atrial defibrillation is to administer multiple shocks, but the administration of multiple shocks typically requires the implantation of additional electrodes.
For ventricular fibrillation, the patient is generally unconscious, the condition is life threatening, and the pain associated with shock is not an issue. It is, however, desirable to reduce the shock strength administered so that the size of the implantable device can be reduced, or to administer shocks in a manner that will decrease the likelihood of recurrence of fibrillation. To meet these objects, it is desirable to administer multiple shocks. Again, the administration of multiple shocks requires the implantation of additional electrodes.
Numerous patients are afflicted with both ventricular and atrial arrhythmias. For such patients, it would be exceedingly desirable to provide a single device that can carry out both atrial and ventricular defibrillation with minimum shock strength, and with minimal surgical intervention.
In view of the foregoing, a first object of the invention is to provide an implantable system for treating cardiac arrhythmia that does not require invasion of the chest cavity for the placement of epicardial electrodes.
A second object of the invention is to provide an implantable cardioversion system wherein the probability of successful cardioversion on administration of the first cardioversion pulse is enhanced, particularly in the case of ventricular fibrillation.
A third object of the invention is to provide an implantable system for treating cardiac arrhythmia that enables reduction of cardioversion, and particularly defibrillation, shock strength.
A fourth object of the present invention is to provide methods and apparatus for carrying out atrial defibrillation that will reduce the pain associated therewith.
A fifth object of the present invention is to provide methods and apparatus for carrying out atrial defibrillation that will reliably treat atrial fibrillation.
A sixth object of the present invention is to provide methods and apparatus for treating atrial fibrillation that minimizes the extent of the surgical intervention involved in implanting the necessary defibrillation electrodes, and minimizes the complexity involved in implanting the necessary defibrillation electrodes.
The foregoing and other objects and aspects of the present invention are described in greater detail in the drawings herein and the specification set forth below.
A first aspect of the present invention is an implantable system for the defibrillation or cardioversion of the atria and the ventricles of a patient""s heart. The system comprises: a first catheter configured for positioning in the right ventricle of the heart; a second catheter configured for positioning through the coronary sinus ostium and in the coronary sinus of the heart, with the first and second catheters together carrying at least three defibrillation electrodes; a power supply; and a control circuit operatively associated with the power supply and the electrodes. The control circuit is configured for delivering an atrial defibrillation pulse through at least two of the electrodes, or a ventricular defibrillation pulse through at least two of the electrodes.
A second aspect of the present invention is an implantable system for the defibrillation or cardioversion of the atria and the ventricles of a patient""s heart. The system comprises: a first catheter configured for positioning in the right ventricle of the heart; a second catheter configured for positioning through the coronary sinus ostium and in the coronary sinus of the heart, with the first and second catheters together carrying at least three defibrillation electrodes; a power supply; and a control circuit operatively associated with the power supply and the electrodes. The control circuit is configured for delivering an atrial defibrillation pulse through at least two of the electrodes, or a ventricular defibrillation pulse through at least two of the electrodes. The system includes a first and second pair of atrial defibrillation electrodes operatively associated with the control circuit and power supply, with the first pair of atrial defibrillation electrodes configured for delivering an atrial defibrillation pulse along a first current pathway and the second pair of atrial defibrillation electrodes configured for delivering a second defibrillation pulse along a second current pathway that is different from the first current pathway, and wherein the control circuit is configured for delivering an atrial defibrillation shock comprising in sequence the first and second atrial defibrillation pulses. Preferably, the system also includes a first and second pair of ventricular defibrillation electrodes operatively associated with the control circuit and the power supply, with the first pair of ventricular defibrillation electrodes configured for delivering a first ventricular defibrillation pulse along a first current pathway and the second pair of ventricular defibrillation electrodes configured for delivering a second defibrillation pulse along a second current pathway that is different from the first current pathway, and wherein the control circuit is configured for delivering a ventricular defibrillation shock comprising in sequence the first and second ventricular defibrillation pulses.
A third aspect of the present invention is an implantable system for the defibrillation or cardioversion of the atria and the ventricles of a patient""s heart. The system comprises: a first catheter configured for positioning in the right ventricle of the heart; a second catheter configured for positioning through the coronary sinus ostium and in the coronary sinus of the heart; with the first and second catheters carrying at least three defibrillation electrodes, with the system including a plurality of primary electrodes configured for delivering a ventricular defibrillation pulse along a predetermined current pathway in a first portion of the heart, the current pathway defining a weak field area in a second portion of the heart, and with the defibrillation electrodes further including at least one auxiliary electrode configured for delivering an auxiliary pulse to the weak field area, with at least one auxiliary electrode configured for positioning through the coronary sinus and in a vein on the surface of the left ventricle of the heart; a power supply; and a control circuit operatively associated with the power supply and the electrodes. The control circuit is configured for delivering an atrial defibrillation pulse through at least two of the electrodes, or a cardioversion sequence comprising a monophasic auxiliary pulse through the auxiliary electrode and a biphasic defibrillation pulse through the primary electrodes. Preferably, the system also includes a first and second pair of atrial defibrillation electrodes, with the first pair of atrial defibrillation electrodes configured for delivering an atrial defibrillation pulse along a first current pathway and the second pair of atrial defibrillation electrodes configured for delivering a second defibrillation pulse along a second current pathway that is different from the first current pathway, and wherein the control circuit is configured for delivering an atrial defibrillation shock comprising in sequence the first and second atrial defibrillation pulses.
A fourth aspect of the present invention is a transvenous catheter for insertion into the heart of a patient, the catheter suitable for use in combination with a combination atrial and ventricular defibrillator. The catheter comprises an elongate lead flexibly configured for insertion down the superior vena cava of the heart, into the right atrium, through the opening of the coronary sinus, through the proximal and distal coronary sinus, and into a coronary vein on the surface of the left ventricle of the heart to achieve an operable configuration therein; a first defibrillation electrode connected to the lead; a second defibrillation electrode connected to the lead at a position distal to the first defibrillation electrode; and a third defibrillation electrode connected to the lead at a position distal to the second defibrillation electrode. The first, second, and third defibrillation electrodes spaced apart on the lead so that, when the catheter is in the operable configuration, the first defibrillation electrode is positioned in the proximal coronary sinus of the heart, the second defibrillation electrode is positioned in the distal coronary sinus or great cardiac vein of the heart, and the third defibrillation electrode is positioned in a coronary vein on the surface of the left ventricle of the heart.